[Cayenne-cvs] cayenne/src/cayenne/java/org/objectstyle/cayenne/util RequestDequeue.java,NONE,1.1 Req

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Update of /cvsroot/cayenne/cayenne/src/cayenne/java/org/objectstyle/cayenne/util
In directory usw-pr-cvs1:/tmp/cvs-serv14437/src/cayenne/java/org/objectstyle/cayenne/util

Added Files:
	RequestDequeue.java RequestQueue.java 
Log Message:
fixed connection pool multithreading problems -
implemented request queue with timeouts


--- NEW FILE: RequestDequeue.java ---
/* ====================================================================
 * 
 * The ObjectStyle Group Software License, Version 1.0 
 *
 * Copyright (c) 2002 The ObjectStyle Group 
 * and individual authors of the software.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        ObjectStyle Group (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "ObjectStyle Group" and "Cayenne" 
 *    must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact an...@ob....
 *
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    nor may "ObjectStyle" appear in their names without prior written
 *    permission of the ObjectStyle Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the ObjectStyle Group.  For more
 * information on the ObjectStyle Group, please see
 * <http://objectstyle.org/>.
 *
 */
package org.objectstyle.cayenne.util;

/**
 * RequestDequeue encapsulates the result of a thread wait in the 
 * RequestQueue.
 * 
 * @author Andrei Adamchik
 */
public class RequestDequeue {
    public static final int DEQUEUE_SUCCESS = 1;
    public static final int QUEUE_FULL = 2;
    public static final int WAIT_TIMED_OUT = 3;

    protected Object dequeueEventObject;
    protected int dequeueEventCode;

    /**
     * Returns the dequeueEventCode.
     * @return int
     */
    public int getDequeueEventCode() {
        return dequeueEventCode;
    }

    /**
     * Returns the dequeueEventObject.
     * @return Object
     */
    public Object getDequeueEventObject() {
        return dequeueEventObject;
    }

    /**
     * Sets the dequeueEventCode.
     * @param dequeueEventCode The dequeueEventCode to set
     */
    public void setDequeueEventCode(int dequeueEventCode) {
        this.dequeueEventCode = dequeueEventCode;
    }

    /**
     * Sets the dequeueEventObject.
     * @param dequeueEventObject The dequeueEventObject to set
     */
    public void setDequeueEventObject(Object dequeueEventObject) {
        this.dequeueEventObject = dequeueEventObject;
    }

    public boolean isDequeueSuccess() {
        return DEQUEUE_SUCCESS == dequeueEventCode;
    }

    public boolean isQueueFull() {
        return QUEUE_FULL == dequeueEventCode;
    }

    public boolean isTimedOut() {
        return WAIT_TIMED_OUT == dequeueEventCode;
    }
}

--- NEW FILE: RequestQueue.java ---
/* ====================================================================
 * 
 * The ObjectStyle Group Software License, Version 1.0 
 *
 * Copyright (c) 2002 The ObjectStyle Group 
 * and individual authors of the software.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        ObjectStyle Group (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "ObjectStyle Group" and "Cayenne" 
 *    must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact an...@ob....
 *
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    nor may "ObjectStyle" appear in their names without prior written
 *    permission of the ObjectStyle Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the ObjectStyle Group.  For more
 * information on the ObjectStyle Group, please see
 * <http://objectstyle.org/>.
 *
 */
package org.objectstyle.cayenne.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * RequestQueue implements a FIFO queue for threads waiting for a 
 * particular event, resource, etc. Each thread will wait 
 * in the queue until either of the following events happen:
 * 
 * <ul>
 *    <li>Thread is already #1 in the queue and an awaited event occurrs</li>
 * 	  <li>Thread timeout interval expired</li>
 * </li>
 * 
 * In both cases thread will be removed from the queue. 
 * 
 * @author Andrei Adamchik
 */
public class RequestQueue {
    protected List queue;
    protected int maxSize;
    protected int timeout;

    /**
     * Constructor for RequestQueue.
     * 
     * @param maxSize - maximum allowed number of 
     * threads in the queue.
     */
    public RequestQueue(int maxSize, int timeout) {
        this.maxSize = maxSize;
        this.timeout = timeout;
        this.queue = Collections.synchronizedList(new ArrayList());
    }

    /**
     * Queues current thread. This will block 
     * the caller till the thread is dequeued as a result
     * of another thread calling <code>dequeueFirst</code>
     * or as a result of a timeout. 
     * 
     * @return an object that represents an event or resource that
     * caused 
     */
    public RequestDequeue queueThread() {
        RequestDequeue result = new RequestDequeue();

        // queue up request
        synchronized (queue) {
            if (maxSize > 0 && queue.size() >= maxSize) {
                result.setDequeueEventCode(RequestDequeue.QUEUE_FULL);
                return result;
            }

            queue.add(result);
        }

        // wait
        synchronized (result) {
            try {
                // release lock and wait
                result.wait(timeout);
            } catch (InterruptedException e) {}

            // wait is over, remove itself from the queue

            if (result.getDequeueEventCode() != RequestDequeue.DEQUEUE_SUCCESS) {

                // timeout
                synchronized (queue) {
                    queue.remove(result);
                    result.setDequeueEventCode(RequestDequeue.WAIT_TIMED_OUT);
                }
            }

            return result;
        }
    }

    /**
     * Releases the first thread in the queue. 
     */
    public boolean dequeueFirst(Object dequeuedObj) {
        synchronized (queue) {
            if (queue.size() > 0) {
                RequestDequeue first = (RequestDequeue) queue.get(0);
                synchronized (first) {
                    queue.remove(0);
                    first.setDequeueEventObject(dequeuedObj);
                    first.setDequeueEventCode(RequestDequeue.DEQUEUE_SUCCESS);
                    first.notifyAll();
                }
                return true;
            }
            else {
            	return false;
            }
        }
    }
}

[Cayenne-cvs] cayenne/src/cayenne/java/org/objectstyle/cayenne/util RequestDequeue.java,NONE,1.1 Req

[Cayenne-cvs] cayenne/src/cayenne/java/org/objectstyle/cayenne/util RequestDequeue.java,NONE,1.1 RequestQueue.java,NONE,1.1